1. Technical Field
The present invention relates to a method for producing a base substrate, a method for producing an electronic device, a base substrate, and an electronic apparatus.
2. Related Art
There has been known an electronic device having a structure in which, for example, a functional device such as an oscillating device is housed in a package. There has also been known a package having a structure in which a base substrate having a recess and a lid covering the opening of the recess are bonded to each other through a bonding layer (a solder material).
In such an electronic device, in order to hermetically seal the internal space of a package, a lid is hermetically bonded to a base substrate. As the bonding method, for example, bonding by laser welding, seam welding, bonding with a low melting point glass, or the like is used. Such bonding by laser welding or the like is performed, for example, as follows. A bonding layer (a metalized layer) is formed on abase substrate, a lid is superimposed over this bonding layer, the bonding layer is irradiated with a laser from the lid side in this state to melt the bonding layer, whereby the lid is bonded to the base substrate through the bonding layer (see, for example, JP-A-2007-63042).
The bonding layer is configured such that an underlayer is formed from W, Mo, Ag, or an alloy thereof, a metal layer of Ni or Ni—P is formed on the underlayer by electroless plating, a metal layer of Pd or Pd—P is formed thereon, and a metal layer of Au is further formed thereon.
However, a crack occurs in such a bonding layer when performing laser welding, resulting in generating a gap in the bonding layer or between the bonding layer and the base substrate, and therefore, a problem arises such that it is difficult to ensure airtightness in the recess.